const hexcase = 0;
const b64pad  = '';
const chrsz   = 8;

function safeAdd(x, y) {
  const lsw = (x & 0xFFFF) + (y & 0xFFFF);
  const msw = (x >> 16) + (y >> 16) + (lsw >> 16);
  return (msw << 16) | (lsw & 0xFFFF);
}

function bitRol(num, cnt) {
  return (num << cnt) | (num >>> (32 - cnt));
}

function md5Cmn(q, a, b, x, s, t) {
  return safeAdd(bitRol(safeAdd(safeAdd(a, q), safeAdd(x, t)), s),b);
}

function md5FF(a, b, c, d, x, s, t) {
  return md5Cmn((b & c) | ((~b) & d), a, b, x, s, t);
}
function md5GG(a, b, c, d, x, s, t) {
  return md5Cmn((b & d) | (c & (~d)), a, b, x, s, t);
}
function md5HH(a, b, c, d, x, s, t) {
  return md5Cmn(b ^ c ^ d, a, b, x, s, t);
}
function md5II(a, b, c, d, x, s, t) {
  return md5Cmn(c ^ (b | (~d)), a, b, x, s, t);
}

function str2binl(str) {
  const bin = [];
  const mask = (1 << chrsz) - 1;
  for(let i = 0; i < str.length * chrsz; i += chrsz)
    bin[i>>5] |= (str.charCodeAt(i / chrsz) & mask) << (i%32);
  return bin;
}

function coreMd5(xx, len) {
  const x = xx;
  x[len >> 5] |= 0x80 << ((len) % 32);
  x[(((len + 64) >>> 9) << 4) + 14] = len;
  let a =  1732584193;
  let b = -271733879;
  let c = -1732584194;
  let d =  271733878;
  for(let i = 0; i < x.length; i += 16)
  {
    const olda = a;
    const oldb = b;
    const oldc = c;
    const oldd = d;

    a = md5FF(a, b, c, d, x[i], 7 , -680876936);
    d = md5FF(d, a, b, c, x[i+ 1], 12, -389564586);
    c = md5FF(c, d, a, b, x[i+ 2], 17,  606105819);
    b = md5FF(b, c, d, a, x[i+ 3], 22, -1044525330);
    a = md5FF(a, b, c, d, x[i+ 4], 7 , -176418897);
    d = md5FF(d, a, b, c, x[i+ 5], 12,  1200080426);
    c = md5FF(c, d, a, b, x[i+ 6], 17, -1473231341);
    b = md5FF(b, c, d, a, x[i+ 7], 22, -45705983);
    a = md5FF(a, b, c, d, x[i+ 8], 7 ,  1770035416);
    d = md5FF(d, a, b, c, x[i+ 9], 12, -1958414417);
    c = md5FF(c, d, a, b, x[i+10], 17, -42063);
    b = md5FF(b, c, d, a, x[i+11], 22, -1990404162);
    a = md5FF(a, b, c, d, x[i+12], 7 ,  1804603682);
    d = md5FF(d, a, b, c, x[i+13], 12, -40341101);
    c = md5FF(c, d, a, b, x[i+14], 17, -1502002290);
    b = md5FF(b, c, d, a, x[i+15], 22,  1236535329);
    a = md5GG(a, b, c, d, x[i+ 1], 5 , -165796510);
    d = md5GG(d, a, b, c, x[i+ 6], 9 , -1069501632);
    c = md5GG(c, d, a, b, x[i+11], 14,  643717713);
    b = md5GG(b, c, d, a, x[i], 20, -373897302);
    a = md5GG(a, b, c, d, x[i+ 5], 5 , -701558691);
    d = md5GG(d, a, b, c, x[i+10], 9 ,  38016083);
    c = md5GG(c, d, a, b, x[i+15], 14, -660478335);
    b = md5GG(b, c, d, a, x[i+ 4], 20, -405537848);
    a = md5GG(a, b, c, d, x[i+ 9], 5 ,  568446438);
    d = md5GG(d, a, b, c, x[i+14], 9 , -1019803690);
    c = md5GG(c, d, a, b, x[i+ 3], 14, -187363961);
    b = md5GG(b, c, d, a, x[i+ 8], 20,  1163531501);
    a = md5GG(a, b, c, d, x[i+13], 5 , -1444681467);
    d = md5GG(d, a, b, c, x[i+ 2], 9 , -51403784);
    c = md5GG(c, d, a, b, x[i+ 7], 14,  1735328473);
    b = md5GG(b, c, d, a, x[i+12], 20, -1926607734);
    a = md5HH(a, b, c, d, x[i+ 5], 4 , -378558);
    d = md5HH(d, a, b, c, x[i+ 8], 11, -2022574463);
    c = md5HH(c, d, a, b, x[i+11], 16,  1839030562);
    b = md5HH(b, c, d, a, x[i+14], 23, -35309556);
    a = md5HH(a, b, c, d, x[i+ 1], 4 , -1530992060);
    d = md5HH(d, a, b, c, x[i+ 4], 11,  1272893353);
    c = md5HH(c, d, a, b, x[i+ 7], 16, -155497632);
    b = md5HH(b, c, d, a, x[i+10], 23, -1094730640);
    a = md5HH(a, b, c, d, x[i+13], 4 ,  681279174);
    d = md5HH(d, a, b, c, x[i], 11, -358537222);
    c = md5HH(c, d, a, b, x[i+ 3], 16, -722521979);
    b = md5HH(b, c, d, a, x[i+ 6], 23,  76029189);
    a = md5HH(a, b, c, d, x[i+ 9], 4 , -640364487);
    d = md5HH(d, a, b, c, x[i+12], 11, -421815835);
    c = md5HH(c, d, a, b, x[i+15], 16,  530742520);
    b = md5HH(b, c, d, a, x[i+ 2], 23, -995338651);
    a = md5II(a, b, c, d, x[i], 6 , -198630844);
    d = md5II(d, a, b, c, x[i+ 7], 10,  1126891415);
    c = md5II(c, d, a, b, x[i+14], 15, -1416354905);
    b = md5II(b, c, d, a, x[i+ 5], 21, -57434055);
    a = md5II(a, b, c, d, x[i+12], 6 ,  1700485571);
    d = md5II(d, a, b, c, x[i+ 3], 10, -1894986606);
    c = md5II(c, d, a, b, x[i+10], 15, -1051523);
    b = md5II(b, c, d, a, x[i+ 1], 21, -2054922799);
    a = md5II(a, b, c, d, x[i+ 8], 6 ,  1873313359);
    d = md5II(d, a, b, c, x[i+15], 10, -30611744);
    c = md5II(c, d, a, b, x[i+ 6], 15, -1560198380);
    b = md5II(b, c, d, a, x[i+13], 21,  1309151649);
    a = md5II(a, b, c, d, x[i+ 4], 6 , -145523070);
    d = md5II(d, a, b, c, x[i+11], 10, -1120210379);
    c = md5II(c, d, a, b, x[i+ 2], 15,  718787259);
    b = md5II(b, c, d, a, x[i+ 9], 21, -343485551);

    a = safeAdd(a, olda);
    b = safeAdd(b, oldb);
    c = safeAdd(c, oldc);
    d = safeAdd(d, oldd);
  }
  return [a, b, c, d];
}

function coreHmacMd5(key, data) {
  let bkey = str2binl(key);
  if(bkey.length > 16) bkey = coreMd5(bkey, key.length * chrsz);

  const ipad = [];
  const opad = [];
  for(let i = 0; i < 16; i += 1) {
    ipad.push(bkey[i] ^ 0x36363636);
    opad.push(bkey[i] ^ 0x5C5C5C5C);
  }

  const hash = coreMd5(ipad.concat(str2binl(data)), 512 + data.length * chrsz);
  return coreMd5(opad.concat(hash), 512 + 128);
}

function binl2hex(binarray) {
  const hexTab = hexcase ? '0123456789ABCDEF' : '0123456789abcdef';
  let str = '';
  for(let i = 0; i < binarray.length * 4; i += 1) {
    str += hexTab.charAt((binarray[i>>2] >> ((i%4)*8+4)) & 0xF)
      + hexTab.charAt((binarray[i>>2] >> ((i%4)*8  )) & 0xF);
  }
  return str;
}

function binl2b64(binarray) {
  const tab = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
  let str = '';
  for(let i = 0; i < binarray.length * 4; i += 3) {
    const triplet = (((binarray[i   >> 2] >> 8 * ( i   %4)) & 0xFF) << 16)
      | (((binarray[i+1 >> 2] >> 8 * ((i+1)%4)) & 0xFF) << 8 )
      |  ((binarray[i+2 >> 2] >> 8 * ((i+2)%4)) & 0xFF);
    for(let j = 0; j < 4; j += 1) {
      if(i * 8 + j * 6 > binarray.length * 32) str += b64pad;
      else str += tab.charAt((triplet >> 6*(3-j)) & 0x3F);
    }
  }
  return str;
}

function hexMd5(s){ return binl2hex(coreMd5(str2binl(s), s.length * chrsz));}
function b64Md5(s){ return binl2b64(coreMd5(str2binl(s), s.length * chrsz));}
function hexHmacMd5(key, data) { return binl2hex(coreHmacMd5(key, data)); }
function b64HmacMd5(key, data) { return binl2b64(coreHmacMd5(key, data)); }
function calcMD5(s){ return binl2hex(coreMd5(str2binl(s), s.length * chrsz));}

function md5VmTest() {
  return hexMd5("abc") === "900150983cd24fb0d6963f7d28e17f72";
}

const md5 = {
  md5(str){
    return hexMd5(str);
  }
};
export default md5;
